Radio communication has become an integral aspect of everyday life in modern society, with a broad range of possible applications. Regardless of the application, clear communication between radio transmitters and radio receivers may be desired. How clear radio communication is, may depend on a number of factors, including signal strength, noise of the device, and interference power. Radio receivers are often designed to meet a worst case scenario for a received signal strength, noise of the devices, and interference power. As such, over-design of receiver components is common, resulting in a waste of power when channel conditions are more benign. This presents an area where power optimization can be improved.
In radio receiver circuit designs, high amplifier gain linearity and minimal noise figures may also be desirable. Noise is an undesirable product of electronic devices and components. One metric for noise figures is a noise factor, which is a measure of how much noise is introduced into the signal being amplified during an amplification process. A noise factor can be a ratio of Signal to Noise Ratio (SNR) of an input signal to the SNR of the amplified output signal.
A radio receiver amplifier with high linearity indicates an ability to control an applied gain. For example, an input signal can be amplified in a linear fashion so as not to modify the signal in any way except amplitude. An ideal amplifier would be a totally linear device, but real amplifiers are only linear within certain practical limits. When an input signal to the amplifier is increased, the output amplified signal also increases until a point is reached where some part of the amplifier becomes saturated and cannot produce any more output. This is typically referred to as clipping, and results in distortion. Amplifiers can be designed to handle clipping in a controlled manner that causes a reduction in gain to occur instead of excessive distortion, for example.